This invention relates an exposure apparatus and a device manufacturing method using the same. More particularly, the invention concerns an exposure apparatus and a device manufacturing method in which a projection exposure step is carried out by using laser light outputted from a continuous emission excimer laser.
For measurement of wavefront aberration of a projection optical system, an interferometer may be incorporated into a projection exposure apparatus. However, if such a light source for such an interferometer is provided separately from a light source for the exposure process, it would lead to bulkiness of the exposure apparatus as a whole.
It is accordingly an object of the present invention to avoid bulkiness of an exposure apparatus which otherwise might result from introduction of an interferometer into the exposure apparatus.
In accordance with an aspect of the present invention, there is provided an exposure apparatus, comprising an illumination optical system for illuminating a pattern of a reticle with laser light outputted from a continuous emission laser; a projection optical system for projecting the illuminated pattern onto a subject to be exposed; and an interferometer operable while using laser light outputted from said continuous emission laser.
In accordance with another aspect of the present invention, there is provided a device manufacturing method, comprising the steps of exposing a wafer to a pattern by use of an exposure apparatus as recited above, and developing the exposed wafer.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.